Materials and systems that statically reflect radiation in the infrared region of the electromagnetic spectrum underpin the performance of many entrenched technologies, including building insulation, energy-conserving windows, spacecraft components, electronics shielding, container packaging, protective clothing, and camouflage platforms. The development of their adaptive variants, in which the infrared-reflecting properties dynamically change in response to external stimuli, has emerged as an important unmet scientific challenge. By drawing inspiration from cephalopod skin, we developed adaptive infrared-reflecting platforms that feature a simple actuation mechanism, low working temperature, tunable spectral range, weak angular dependence, fast response, stability to repeated cycling, amenability to patterning and multiplexing, autonomous operation, robust mechanical properties, and straightforward manufacturability. Our findings may open opportunities for infrared camouflage and other technologies that regulate infrared radiation.

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Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensor and transducer material due to its high piezo-, pyro-and ferroelectric properties. To activate these properties, PVDF films require a mechanical treatment, stretching or poling. In this paper, we report on a force sensor based on PVDF fabrics with excellent flexibility and breathability, to be used as a specific human-related sensor. PVDF nanofibrous fabrics were prepared by using an electrospinning unit and characterized by means of scanning electron microscopy (SEM), FTIR spectroscopy and x-ray diffraction. Preliminary force sensors have been fabricated and demonstrated excellent sensitivity and response to external mechanical forces. This implies that promising applications can be made for sensing garment pressure, blood pressure, heartbeat rate, respiration rate and accidental impact on the human body.

robotics. [9,10] More recently, the emergence of analogous platforms that dynamically modulate the propagation of IR radiation (i.e., heat) has facilitated exciting proof-of-principle demonstrations in areas such as energy conservation, [11,12] thermal management, [13,14] and IR camouflage. [15,16] Within this context, devices or systems that can potentially manipulate light across both the visible (400-740 nm) and IR (740 nm to 15 µm) spectral regions remain quite rare. To date, relatively few classes of these technologies have been reported, such as thermochromic phase-change materials, [17][18][19][20] electrochromic devices, [21][22][23] IR-reflecting platforms, [24,25] and reconfigurable soft machines [9] (see Table S1, Supporting Information), and they have featured drawbacks that include a limited degree of spectral modulation, impractical actuation requirements, poor stability to repeated actuation, slow response times, and/or complicated fabrication. [9,[17][18][19][20][21][22][23][24][25] Indeed, the engineering of devices and systems with tandem adaptive functionality across a broad spectral window (i.e., encompassing the visible, near-IR, short-wavelength IR, mid-wavelength IR, and long-wavelength IR) has proven challenging, in part because of the order of magnitude difference in the length scales associated with the propagation of visible and long-wavelength IR light. Consequently, there exists an impetus for the development of advanced multimodal camouflage platforms, which can present new scientific and technological opportunities across multiple fields.Some of the most prominent and impressive examples of soft, deformable systems that can reversibly and precisely change their appearance are found in nature-they are animals called coleoid cephalopods, [26][27][28][29][30][31][32] such as the Japetella heathi pelagic octopus (Figure 1A) [28] and the Taonius borealis glass squid ( Figure 1B). [29,30] These animals are capable of stunning feats of concealment, which include changing the transparency of their bodies by means of a sophisticated skin architecture that controls the transmission, absorption, and reflection of light ( Figure 1C). [26][27][28][29][30][31][32] In its most general form, the skin consists of multiple layers containing pigmented sizechanging organs called chromatophores, [33][34][35] typically narrowband-reflecting cells called iridophores, [36][37][38] and broadbandreflecting cells called leucophores [39][40][41] (Figure 1C). Although their precise arrangement and optical functionalities tend to Soft, mechanically deformable materials and systems that can, on demand, manipulate light propagation within both the visible and infrared (IR) regions of the electromagnetic spectrum are desirable for applications that include sensing, optoelectronics, robotics, energy conservation, and thermal management. However, the development of such technologies remains exceptionally difficult, with relatively few examples reported to date. Herein, this challenge is addressed by engineering ceph...

Artificial skin that simultaneously mimics sensory feedback and mechanical properties of natural skin holds substantial promise for next-generation robotic and medical devices. However, achieving such a biomimetic system that can seamlessly integrate with the human body remains a challenge. Through rational design and engineering of material properties, device structures, and system architectures, we realized a monolithic soft prosthetic electronic skin (e-skin). It is capable of multimodal perception, neuromorphic pulse-train signal generation, and closed-loop actuation. With a trilayer, high-permittivity elastomeric dielectric, we achieved a low subthreshold swing comparable to that of polycrystalline silicon transistors, a low operation voltage, low power consumption, and medium-scale circuit integration complexity for stretchable organic devices. Our e-skin mimics the biological sensorimotor loop, whereby a solid-state synaptic transistor elicits stronger actuation when a stimulus of increasing pressure is applied.